[[Image:NEOWEB2.png|thumb|450px|Modulating the polarization state of an optical beam passing through an electro-optic crystal.]]
[[Image:NEOWEB3.png|thumb|450px|A normal electro-optic field probe sampling the electric field of a device under test.]]
The NeoScan real-time field measurement & scanning system provides an entirely new capability for the measurement of high-intensity electric fields. This technology is based on the Pockel’s effect which measures the phase-retardance of an optical beam due to an impinging electric field. This electro-optic effect is observed in non-centrosymmetric crystals when an electric field is directed along certain crystal axes causes a change in the indices of refraction encountered by an incident optical beam. Figure 1.1 shows the basic principle of the electro-optic effect. The electro-optic effect provides a means of modulating the phase or intensity of the optical radiation. In another sense, this effect also makes it possible to detect the presence of an electric field impinging on the crystal. The polarization of an optical beam travelling through a crystal is altered by the electric field in that crystal. The comparison of polarization states allows determination of the amplitude and phase of the existing RF electric field. Since the electro-optic sensing phenomenon relies on small displacements of the atomic crystal structure, the response time of the process is extremely short. This short response time makes it possible to measure high-frequency electric fields up to the terahertz regime.
Due to the fast response of the EO crystal, it is possible to measure extremely high-bandwidth signals with the normal SNR limitations of wideband signal detection. Using this capability, EMAG Technologies Inc. has developed the world’s first fiber-based real-time polarimetric electric field sensor system – NeoScan – for the measurement of high-power microwave signals. Figure 1.4 is an example of a real time measurement of a 6.6 nsec pulse with 10 kV/m peak field strength. The upper trace shown on the oscilloscope is the received signal, and the lower trace is the detected signal.
[[Image:NEOWEB3.png|thumb|450px|A normal electro-optic field probe sampling the electric field of a device under test.]]
The NeoScan system is capable of measuring signals with bandwidths up to 20 GHz and signal levels as low as 1 V/m for optical probes with a 10 m PM fiber. Because the optical probes are free of metallic parts, it is possible to measure extremely high-field strengths since there are no free electron surfaces to generate arcing. The NeoScan can measure fields up at least 2 MV/m and possibly higher.